Uphill vs. downhill makes the biggest difference

[fuzzy1]

Originally Posted by ken1784

...
My car inspection sheet says 1290kg empty. I'm a skinny person, so I set 1350kg test vehicle weight. ...

This helps explains much of the difference. A US Gen3 is much heavier than your Gen2 was, and I'm not as skinny as you. Neither is my wife. Including some equipment, my car weight for this trip was probably about 1560 kg.

Originally Posted by bwilson4web

Averaging the center three or lower four, we get:

0.904 gal / 10,000 ft (middle three)
0.888 gal / 10,000 ft (lower four)
0.846 gal / 10,000 ft (lower three)

This is what we'd call an informed guess, back of the envelope, or best estimate of hill climb fuel consumed as a function of altitude. Without a series of benchmarks at different speeds along with or using HSI settings, we don't have enough information to call out an exact hill climb curve. Regardless, a rule of thumb like this can help with trip planning ... YMMV (your mileage may vary.) ...

This is becoming more solid than my original 1 gal / 10,000 feet rule of thumb. I'll try to take more data on an upcoming vacation with considerable altitude change, but it will be a loop, not an out-and-return trip, so any figures will be harder to interpret.

[usbseawolf2000]

Prius can climb hills easy due to the huge MG2 torque. See the video below of me climbing with my wife in the passenger seat. Yes, the speed is low but so is the engine RPM (about 1,500). HSD was working like a series hybrid (such as Volt). Gas engine was making power to feed to the electric motor to get a huge torque boost. A step gear car will not be able to do it.

YouTube - The Power of Hybrid Synergy Drive to Climb Hill

YouTube - The Power of Hybrid Synergy Drive to Climb Hill

Below is the slope of the hill in the above video:


In the video below, a friend with 1996 Civic and I (with 2006 Prius) experimented with hill climbing. Although the Civic is much lighter, the engine almost stalled when the RPM gets as low as my Prius.

YouTube - Comparison of 1996 Civic (1.6l) Vs. 2006 Prius (1.5l)

YouTube - Comparison of 1996 Civic (1.6l) Vs. 2006 Prius (1.5l)

To highlight the benefit of the synergy between gas and electric, I am going to compare and contrast the two:

	Prius	Civic
ICE Displacement	1.5l	1.6l
ICE Torque	82 lbs-ft	105 lbs-ft
ICE Power	76 hp	106 hp
Total Power	110 hp	106 hp
Car weight	2,900 lbs	2,300 lbs
Passenger Volume	96 cu.ft.	90 cu.ft.
Cargo Volume	16 cu.ft.	12 cu.ft
Combined FE	46 mpg	31 mpg

[fuzzy1]

Originally Posted by usbseawolf2000

... Below is the slope of the hill in the above video:

I'm missing something.

First, a caveat. Normal pictures are terrible for showing me steep slopes, the camera view tends to flatten perceptions.

The first video claims the hill has a 15-20 degree slope. But the ground lines on two foundations measure out on my display as 16 and 17 %, which convert to between 9 and 10 degrees, much less steep than advertised.

Your graph appears to have a rise of about 120 feet in 0.2 mile, a slope of only 11%, or 6.5 degrees.

These numbers are not particularly steep. What am I missing?

[usbseawolf2000]

Originally Posted by fuzzy1

Your graph appears to have a rise of about 120 feet in 0.2 mile, a slope of only 11%, or 6.5 degrees.

These numbers are not particularly steep. What am I missing?

The graph should be more accurate as it came from using this tool.

The 15-20 degree was my guess when I edited that video and I am surprise I was way off. From what you saw in the video, does it look like 6.5 deg angle hill?

[PriusRos]

Here's a typical Consumption display readout for my area. I took this particular snapshot last night at the end of a 450-mile drive, so the average mpg is higher than my usual commuting average. However, what is typical is the big variations in the 1-minute readings. The 50-plus to 100mpg readings are when I am going downhill while the 35 to under-50 mpg readings are when I am going uphill. It's almost like an inverted pictures of the hills themselves !

[Ceczech8]

Hi all, First post!

Anyways, I am still on my first tank of gas (just bought the car 11/9/09) and have a "lifetime" average of 46 mpg. I thin that is somewhat typical for what I drive in a day.

55 mile commute to work on a 1000 ft difference (Start high and go low, then reverse it back home)... To work I average 51.3 mpg. To home I average about 43. My total average is about 46.6. I think it will get better once the car/motor is broken in more. The hills and mountains on the PA interstates is what kills the mpg.

[LakePrius]

I've done a bunch of round trips in my 2010 of 300-400 miles. The first 70ish miles are pretty much downhill - from 10,000 feet to sea level. Over this first part I tend to get about 92-93 MPG. By the time I hit 150-200 miles, I'm down to about 65 MPG and then into the mid 50's on the return trip before I start back up the hill. By the time I'm home I've averaged 52-53 MPG over the entire distance.

This is about the same MPG I get just driving around town without a lot of concern about driving style - but still taking opportunities to make the instantaneous gauge hit 100 when possible.

So my experience is in the end it all just seems to average out to about the same thing.